Installing Python in local directory
On one of our client’s Ubuntu 10.04 machines, I needed to upgrade Python from 2.6 to 2.7. Unfortunately, after installing Python 2.7 from apt the virtualenv, version 1.4.5, did not work correctly. This bug was fixed in a newer virtualenv version, however there were no Ubuntu packages available.
I thought about trying something else: why not install all the software locally in my home directory on the server? When virtualenv is used to create a new environment, it copies the Python executable in to the virtualenv directory.
First I install pythonbrew, which is great software for installing many different Python versions in a local directory.
$ curl -kL http://xrl.us/pythonbrewinstall | bash
Then I activate pythonbrew with:
$ source "$HOME/.pythonbrew/etc/bashrc"
And install the Python version I want:
$ pythonbrew install 2.7.3
The installation took a couple of minutes. The script downloaded the tarball with the Python source code for the required version, compiled it and installed. It was writing all the information into a log file, which I was looking at by running the command below in another console:
$ tail -f $HOME/.pythonbrew/log/build.log
You can also add the following lines to ~/.bashrc to activate this python after starting new bash session.
[[ -s "$HOME/.pythonbrew/etc/bashrc" ]] && source $HOME/.pythonbrew/etc/bashrc pythonbrew switch 2.7.3
I run the below command to activate the pythonbrew script:
$ source $HOME/.pythonbrew/etc/bashrc
The python version changed:
$ python --version Python 2.6.5 $ source $HOME/.pythonbrew/etc/bashrc $ python --version Python 2.7.2
As you can see, Python from my local installation is used:
$ which python /home/szymon/.pythonbrew/pythons/Python-2.7.3/bin/python
The only thing left is to create the virtual environment for the new Python version. I use virtualenvwrapper for managing virtualenv, so the obvious way to create a new environment is:
$ mkvirtualenv --no-site-packages envname
Unfortunately, it creates an environment with the wrong Python version:
$ which python /home/szymon/.virtualenvs/envname/bin/python $ python --version Python 2.6.5
So let’s try to tell virtualenvwrapper which Python file should be used:
$ deactivate $ rmvirtualenv envname Removing envname... $ mkvirtualenv --no-site-packages -p /home/szymon/.pythonbrew/pythons/Python-2.7.3/bin/python envname
Unfortunately this ended with an error:
Running virtualenv with interpreter /home/szymon/.pythonbrew/pythons/Python-2.7.3/bin/python New python executable in envname/bin/python Traceback (most recent call last): File "/home/szymon/.virtualenvs/envname/lib/python2.7/site.py", line 67, in <module> import os File "/home/szymon/.virtualenvs/envname/lib/python2.7/os.py", line 49, in <module> import posixpath as path File "/home/szymon/.virtualenvs/envname/lib/python2.7/posixpath.py", line 17, in <module> import warnings ImportError: No module named warnings ERROR: The executable envname/bin/python is not functioning ERROR: It thinks sys.prefix is '/home/szymon/.virtualenvs' (should be '/home/szymon/.virtualenvs/envname') ERROR: virtualenv is not compatible with this system or executable </module></module></module>
The problem is that the virtualenv version, used by virtualenvwrapper, doesn’t work with Python 2.7. As I wrote at the begining, there is no newer version available via apt. The solution is pretty simple. Let’s just install the newer virtualenvwrapper and virtualenv version using pip.
$ pip install virtualenv Requirement already satisfied: virtualenv in /usr/lib/pymodules/python2.6 Installing collected packages: virtualenv Successfully installed virtualenv
As you can see, there is a problem. The problem is that there is used pip from system installation. There is no pip installed in my local Python 2.7 version. However there is easy_install:
$ which pip /usr/bin/pip $ which easy_install /home/szymon/.pythonbrew/pythons/Python-2.7.3/bin/easy_install
So let’s use it for installing virtualenv and virtualenvwrapper:
$ easy_install virtualenv virtualenvwrapper
I’ve checked the whole installation procedure once again, it turned out that there was some network error while downloading pip, but unfortunately I didn’t notice the error. If everything is OK, then pip should be installed, and you should be able to install virtualenv using pip as well with:
$ pip install virtualenv virtualenvwrapper
Cool, let’s check which version is installed:
$ which virtualenv /home/szymon/.pythonbrew/pythons/Python-2.7.3/bin/virtualenv $ virtualenv --version 1.8.4
Before creating the brand new virtual environment, I have to activate the new virtualenvwrapper. I have the following line in my ~/.bashrc file:
I just have to change it to the below line and login once again:
Let’s now create the virtual environment using the brand new Python version:
$ mkvirtualenv --no-site-packages -p $HOME/.pythonbrew/pythons/Python-2.7.3/bin/python envname
I want to use this environment each time I log into this server, so I’ve added this line to my ~/.bashrc:
Let’s check if it works. I’ve logged out and logged in to my account on this server before running the following commands:
$ which python /home/szymon/.virtualenvs/envname/bin/python $ python --version Python 2.7.3
Looks like everything is OK.